1. Field of the Invention
The present invention relates to a liquid crystal display, and a method for transferring its signal, and a liquid crystal panel. More particularly, the present invention relates to a technique for compactly designing a liquid crystal display and reducing its manufacturing cost.
2. Description of the Related Art
Conventionally, a liquid crystal display used as a display in a computer or the like has been well known. This liquid crystal display is composed of a liquid crystal panel and a drive circuit for driving this liquid crystal panel. The liquid crystal panel is designed such that cells are arranged in matrix at respective intersections of a plurality of signal lines in an X-axis direction and a plurality of signal lines in a Y-axis direction. The drive circuit includes a drive circuit for driving the signal lines in the X-axis direction and another drive circuit for driving the signal lines in the Y-axis direction.
The drive circuit for driving the signal lines in the X-axis direction is mounted on a substrate referred to as xe2x80x9cgate driver substratexe2x80x9d. This gate driver substrate is placed on any one of a left side and a right side of the liquid crystal panel. Also, the other drive circuit for driving the signal lines in the Y-axis direction is mounted on a substrate referred to as xe2x80x9csource driver substratexe2x80x9d. This source driver substrate is placed on any one of an upper side and a lower side of the liquid crystal panel.
As a screen of the liquid crystal panel becomes larger, the distances in the X-axis direction and the Y-axis direction increase. For this reason, a distance from a drive source to the cell becomes longer and thereby a resistance of the signal line from the drive source to the cell becomes greater. This causes a delay of a signal received by cells that are farther from the drive source. When this phenomenon occurs, a standard voltage is not supplied to an electrode of. the cell. Hence, a normal operation cannot be carried out.
Materials of the signal lines have been changed so as to reduce a resistance value. However, this increases the steps in the manufacturing process of the liquid crystal panel, making the liquid crystal display more expensive. To solve this problem and also cope with a larger size of the liquid crystal screen, the gate driver substrates have been mounted on both the left and right sides of the liquid crystal panel. In this case, the signal lines in the respective X-axis directions are driven from both the left and right sides.
However, when the gate driver substrates are mounted on both sides of the liquid crystal panel, it is necessary to extend cables to the two gate driver substrates. Thus, space for parts mounted in a periphery of the liquid crystal panel becomes limited, which brings about a problem that the liquid crystal display can not be made compact. Also, because a cable having a length that approximately crosses the liquid crystal panel in a left and right direction, the treatment of the cable is complex. Moreover, it is necessary to connect the two gate driver substrates to the liquid crystal panel. Hence, this also causes a problem that a connecting process is increased to thereby make the liquid crystal display expensive.
As a related technique, Japanese Patent No.2655061 discloses xe2x80x9cLIQUID CRYSTAL DISPLAYxe2x80x9d which can use one kind of a horizontal connection substrate for a first connection substrate and a second connection substrate by properly using a terminal of the horizontal connection substrate. However, this liquid crystal display is designed such that the two substrates are connected through a cable to each other. Thus, the above-mentioned problems can not be solved.
Japanese Laid Open Patent Application (3P-A-Heisei, 9-211484) disclolses xe2x80x9cLIQUID CRYSTAL DISPLAYxe2x80x9d. In this liquid crystal display, a flexible circuit substrate connected to a first terminal electrode and a second terminal electrode placed on a liquid crystal panel is integrally formed into a single unit. The flexible circuit substrate has a rollup section for partially rolling up a portion that is not related with the connection of the first and second terminal electrodes of the flexible circuit substrate. However, this liquid crystal display does not solve the above-mentioned problems since the two substrates are connected to each other through a cable of a kind that is called a flexible circuit substrate.
The present invention has been made to solve the above-described problems, and therefore, has an object to provide a liquid crystal display, a method for transferring its signal, and a liquid crystal panel, which can be made compact and further manufactured at a low cost.
A liquid crystal display according to a first aspect of the present invention, in order to attain the above-mentioned object, includes a liquid crystal panel, a first gate driver substrate, a second gate driver substrate and a source driver substrate. The liquid crystal panel includes cells arrayed in matrix. The first substrate is provided in a first outer portion of the liquid crystal panel, and has a first drive circuit provided to drive a set of signal lines in an X-.axis direction of the liquid crystal panel. The second substrate is provided in a second outer portion opposite to the first outer portion of the liquid crystal panel, and has a second drive circuit provided to drive another set of signal lines in the X-axis direction of the liquid crystal panel. The third substrate is provide between the first substrate and the second substrate, and has a third drive circuit provided to drive a set of signal lines in a Y-axis direction of the liquid crystal panel. Also, the third substrate includes a wiring pattern through which a signal sent to at least one of the first substrate or the second substrate is passed.
This liquid crystal display according to the first aspect of the present invention may be designed such that the first substrate has the same structure as the second substrate, and the first substrate has the same wiring pattern as the second substrate. Thus, one kind of substrate can be commonly used as the first and second gate driver substrates. Hence, its manufacturing cost can be made cheaper as compared with the case when two kinds of substrates are produced.
This liquid crystal display according to the first aspect of the present invention may be designed such that the first substrate further comprises a first part whose one end is connected to the first drive circuit, and the second substrate further comprises a second part whose one end is connected to the second drive circuit. In this liquid crystal display, a predetermined potential may be applied to another end of the first part mounted on the first substrate, and another potential may be applied to another end of the second part mounted on the second substrate. In this case, the first part and the second part may be composed of resistors, respectively. According to this configuration, two kinds of functions can be attained depending on whether resistors serving as the first and second parts are connected to a power supply or a ground.
The liquid crystal panel according to the first second aspect of the present invention may be designed such that in the liquid crystal panel, a first connection terminal for connecting the first drive circuit is formed in a first inner portion of the liquid crystal panel, and a second connection terminal for connecting the second drive circuit is formed in a second inner portion opposite to the first inner portion of the liquid crystal panel, and the first connection terminal and the second connection terminal are arranged in a line symmetry with respect to a line passing through a middle point in the Y-axis direction of the liquid crystal panel.
The liquid crystal panel according to the first second aspect of the present invention may be designed such that in the liquid crystal panel, a first connection terminal for connecting the first drive circuit is formed in a first inner portion of the liquid crystal panel, and a second connection terminal for connecting the second drive circuit is formed in a second inner portion opposite to the first inner portion, and the first connection terminal and the second connection terminal are arranged in a point symmetry with respect to an intersection of a line passing through a middle point in the Y-axis direction of the liquid crystal panel and another line passing through a middle point in the X-axis direction of the liquid crystal panel.
A liquid crystal panel according to a second aspect of the present invention, for the above-mentioned similar object, includes cells, a first connection terminal, and a second connection terminal. The cells are arrayed in matrix. The first connection terminal is formed in a first inner portion of the liquid crystal panel, and connected to a first drive circuit provided to drive a set of signal lines in an X-axis direction. The second connection terminal is formed in a second inner portion opposite to the first inner portion of the liquid crystal panel, and connected to a second drive circuit provided to drive another set of signal lines in the X-axis direction. Here, the first connection terminal and the second connection terminal are arranged in a line symmetry with respect to a line passing through a middle point in an Y-axis direction of the liquid crystal panel.
The liquid crystal panel according to the second aspect of the present invention may be designed such that the first connection terminal and the second connection terminal are arranged in a point symmetry with respect to an intersection of a line passing through a middle point in an Y-axis direction of the liquid crystal panel and a line passing through a middle point in the X-axis direction of the liquid crystal panel.
A method for transferring a signal in a liquid crystal display according to a third aspect of the present invention includes providing step and transferring step. In the providing step provides a liquid crystal panel in which cells are arrayed in matrix, a first substrate which is provided in a first outer portion of the liquid crystal panel, and has a first drive circuit provided to drive a set of signal lines in an X-axis direction of the liquid crystal panel, a second substrate which is provided in a second outer portion opposite to the first outer portion of the liquid crystal panel, and has a second drive circuit provided to drive another set of signal lines in the X-axis direction of the liquid crystal panel, and a third substrate which is provide between the first substrate and the second substrate, and has a third drive circuit provided to drive a set of signal lines in a Y-axis direction of the liquid crystal panel. The transferring step transfers a signal to at lease one of the first substrate and the second substrate through a wiring pattern formed on the third substrate.